Elongate tubular devices, such as diagnostic or treatment catheters or sheaths may be provided for introduction into a patient's body, e.g., the patient's vasculature or other body lumens. For example, a catheter may have a distal portion configured to be introduced into a body lumen and advanced to one or more desired locations within the patient's body by manipulating a proximal end of the catheter.
To facilitate introduction of such a catheter, one or more wires, cables, or other steering elements may be provided within the catheter, e.g., that are coupled to the distal portion and may be pulled or advanced from the proximal end to deflect the distal portion. For example, a steering element may be provided that is intended to deflect the distal portion within a predetermined plane and/or into a desired curved shape.
Pull wires are a common way to impart deflection ability to such a catheter. The pull wire may be slidably disposed within a lumen of the catheter that extends from the proximal end to the distal where a distal end of the pull wire is coupled to the distal end of the catheter. A proximal end of the pull wire may be coupled to an actuator provided on a handle coupled to the proximal end of the catheter. When a proximal tension is applied to the pull wire, e.g., by directing the actuator proximally, it may cause a distal portion of the catheter to curve or otherwise deflect in a first direction. However, the actuator may not be generally directed distally with equal effect to cause the distal portion to curve or deflect in a second opposite direction. Instead, a second pull wire may be provided that be offset from the first pull wire and actuated to deflect the distal portion in the second opposite direction.
Accordingly, there is a need for improved steerable catheters, sheaths, and other tubular devices and for handles and/or actuators for such tubular devices.